A line width compensation module and compensation method applied to dqpsk system

Abstract

The invention discloses a line width compensation method and a line width compensation module applied to a DQPSK (differential quadrature phase shift keying) system. The method includes: preprocessing empty and full portions of vector signal data by equal-proportional amplification; taking continuous N data as a group, subjecting the first group of data with phase pre-compensation initial values being 0 to phase pre-compensation, subjecting the next group of data to phase pre-compensation, calculating to obtain residual phase noise amplitude by means of phase amplification and normalization for pre-compensation of each group of vector signal data, averaging N phase data, dividing an average value by four to obtain a residual phase shift value, subjecting the pre-compensated data to residual phase noise compensation according to the residual phase shift value, and adding the residual phase shift value of the current data group to a pre-compensation phase value to obtain a value serving as a phase pre-compensation value for phase compensation of the next group of N data. The line width compensation method and a line width compensation module have the advantages that influences on signal phases due to line width effects of a light source of the DQPSK system are effectively compensated, and computational complexity is lowered.

Description

technical field [0001] The present invention relates to a line width compensation module and its compensation method applied to a DQPSK (Differential Quadrature Reference PhaseShift Keying) system. The method and device can reduce the requirement of the DQPSK system for the line width of a light source. The present invention belongs to the field of communication. Background technique [0002] With the advancement of communication technology, the polarization multiplexed phase-shift keying coherent optical communication system can achieve a communication rate that is multiple times the symbol rate when the symbol rate is constant, and at the same time it can support the existing optical transmission network and related Passive components such as optical amplifiers and isolators are fully compatible. Moreover, the processing of optical signals is all transferred to the electrical domain, which reduces the requirements for optical devices and can obtain greater signal processi...

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Problems solved by technology

[0004] In the existing literature, the quartic method is mainly used for linewidth phase noise compensation. The disadvantage of this method is that the range of phase noise that can be compensated is limited, and the size must not exceed (-π / 4,+π / 4); When the phase size exceeds the limit, it is necessary to use the phase jump detection method. Since the calculation of N data is performed each time, when the phase is on the edge of the limit, it is likely to cause misjudgment and lead to bit errors. This method requires a large The amount of calculation, and the calculation accuracy is poor, and the tolerance to other phase noise is also low

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